Question: Which of the following numbers is a multiple of 10? ${69,80,97,108,113}$
Answer: The multiples of $10$ are $10$ $20$ $30$ $40$ ..... In general, any number that leaves no remainder when divided by $10$ is considered a multiple of $10$ We can start by dividing each of our answer choices by $10$ $69 \div 10 = 6\text{ R }9$ $80 \div 10 = 8$ $97 \div 10 = 9\text{ R }7$ $108 \div 10 = 10\text{ R }8$ $113 \div 10 = 11\text{ R }3$ The only answer choice that leaves no remainder after the division is $80$ $ 8$ $10$ $80$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $10$ are contained within the prime factors of $80$ $80 = 2\times2\times2\times2\times5 10 = 2\times5$ Therefore the only multiple of $10$ out of our choices is $80$. We can say that $80$ is divisible by $10$.